The present invention relates to a food cooking oven with fan-assisted operation which is adapted to perform cooking cavity cleaning automatically.
In the following description, reference is made, in particular, to a food cooking oven of the type intended for use in catering operations, professional kitchens and similar applications. It will, however, be appreciated that what is described and claimed in connection thereto in this patent actually applies to any kind of food cooking oven.
It is generally known that, during cooking of foodstuffs in an oven, and especially during fan-assisted operation of such an oven, the cooking cavity thereof is subject to quick and heavy soiling by splashes of food particles, juice, and gravy droplets. In particular, in the case of ovens with fan-assisted operation, air becomes impregnated with emanations (air-borne soil) from the food being cooked and deposits them on the walls of the oven cavity. If a sufficiently high temperature is prevailing in the oven cavity, such particles being deposited on the walls thereof become thermally set thereon due to their burning and charring.
Such a soiling of the oven cavity is a wholly undesired effect, since it gives rise to a number of well-known drawbacks which are discussed hereafter only for the sake of a better understanding of the problem. First of all, the very presence of food remainders in the oven cavity brings about the possibility of decay and putrefaction thereof, with obvious risks of a hygienic and sanitary nature resulting therefrom. Furthermore, such food residues deposited onto the oven cavity walls, especially when they are not burned or charred, are generally subject to progressive deterioration as they go through subsequent cooking cycles in the oven cavity, and tend to dissolve by giving off fumes and unpleasant odors.
These drawbacks are generally tolerated to a certain extent when they relate to cooking ovens used in household applications, where there is no definite obligation set by external authorities governing the way in which oven cavities should be cleaned. However, even in household applications such a problem is being felt to such an extent that the solution consisting of providing the ovens with a so-called "self-cleaning" feature is widely known to have rapidly expanded in the marketplace. Presently, self-cleaning ovens are generally provided with plates that clad the oven cavity walls and are provided with a special pyrolytic coating. Upon conclusion of the actual cooking process, the temperature in these ovens is increased to a value of up to approximately 400.degree. C., so that the pyrolytic coating is enabled to "burn off" and dissolve the food residues deposited on it.
Such a solution, however, suffers from a number of drawbacks. First of all, it requires a considerable use of energy to boost the temperature inside the cooking cavity to the required, typically high, self-cleaning value. Furthermore, this self-cleaning process has proven to be just partially effective, since it fails to remove possible soil particles that are not deposited directly on the pyrolytic plates. A third drawback results from the fact that self-cleaning plates with pyrolytic coatings are typically subject to become exhausted in a relatively quick way, thereby losing their self-cleaning property.
The problem of adequately keeping the inside of the oven cavity in a clean state is felt in a particularly acute way in the use of the ovens for cooking foods in catering establishments and professional kitchens in general. There, the need for systematically cleaning the cooking cavity arises both from definite requirements set by standard regulations and the fact that such ovens are typically subject to heavy-duty utilization. That is, they are used in an intensive way, many times each day throughout the year.
After each cooking cycle, the oven operator is required to clean the interior of the cooking cavity. A cooking cycle is, in this case, understood to mean a sequence or a certain number of subsequent cooking processes. A standardized method of cleaning the oven cavity consists of manually spraying a certain amount of very alkaline detergent substances onto the cavity walls, shutting the oven door and allowing the detergent substances to chemically attack the cooking residues to be removed for an adequate period of time, which typically cannot be shorter than approximately 15 minutes. Then the operator opens the oven door and manually cleans and rinses the cavity to remove the residues as decomposed by the detergent substances.
Such a cleaning method is usually very unpleasant for the oven operators due to the ill-smelling fumes and aggressive vapors that are emitted when the oven door is eventually opened to reach inside the cavity for cleaning. Furthermore, the subsequent rinsing phase, due to the fact that it must be performed by hand and generally requires a lot of time to be carried out, tends to make operators unavailable just when full personnel availability is required in the kitchen for food preparation purposes.
The need therefore arises to provide an oven, especially one capable of being use in commercial and institutional catering establishments, which is adapted to perform a fully automatic self-cleaning process in a most simple way. The oven should be cleaned without any involvement whatsoever of the operator, as well as without this implying any need to carry out any significant design and/or construction modifications in the ovens themselves.